A STUDY ON THE MIDDLE HOLOCENE FIRE HISTORY AND ITS INFLUENCING FACTORS IN NINGSHAO PLAIN
Ningshao Plain is an ideal place to investigate the intricate relationship among Holocene fire events,climate,environment and human activities.In this study,two sediment cores from Tianluoshan site(30°01′20″N,121°22′38″E)and Jingtoushan site(30°01′28.45″N,121° 21′40.69″E)measured 18.17 m and 19.8m,and most of the samples were dated at 8500～6000 cal.a B.P.respectively,were utilized to conduct charcoal and pollen analysis,and we examined the fire history,climate and environmental changes,as well as human influence during the Middle Holocene(9000～5700 cal.aB.P.)in Ningshao Plain.The findings indicate that during the Early and Middle Holocene,the charcoal concentrations in both cores were very low.The Tianluoshan core exhibited the lowest levels of fine,medium,and coarse charcoal concentrations within its profile,which is indicative of infrequent fire occurrences during that period.Throughout the Holocene Climate Optimum characterized by a robust Asian summer monsoon and abundant precipitation,pollen records also showed the vegetation type at this time was subtropical broadleaf forest,and the warm and humid climate was not conducive to the occurrence of fire events.With the hydrological environment in the study area exhibiting stability,abundant resources attracted human beings to settle,and intensified human activities have resulted in increased frequency of fire events and elevated charcoal concentration levels.Around 7900cal.aB.P.,as the rate of sea level rise decelerated,human ancestors chose to settle in the Jingtoushan area and initiated early attempts at rice agriculture,which coincided with a increase in charcoal concentration.After 7000 cal.a B.P.,the freshwater wetlands in the study area were extensively distributed,giving rise to the Hemudu culture and leading to an increase in charcoal concentration.The charcoal concentration in Tianluoshan core reached its maximum value in 6300 cal.a B.P.However,during this period,the environment in the study area remained unstable and continued to be influenced by seawater intrusion between 7000～6000 cal.aB.P.The low charcoal concentration observed in the Tianluoshan core can be attributed to the seawater influence.After 5900cal.aB.P.,the study area transitioned into an entirely land-based region,facilitating flourishing rice agriculture and resulting in a significant increase in charcoal concentration.This study investigates the relationship among the Middle Holocene fire events,climate,environment and human activities in Ningshao Plain.It elucidates the impact of climate and human activities on fire occurrences in this region,thereby offering a novel perspective for future research endeavors in this area.
万方数据
维普
